Blender collada import export, sketchup comparison
I don't know Sketchup for it's not open-source neither do I use it much but let me explain Blender's collada exporter.

First why is Collada so unique other than it being libre(open), 


  COLLADA is designed to be highly flexible. It can store
  application-specific data using its  mechanism at various
  places in the document. You can insert this data in your DCC tool
  using the user properties mechanism; the COLLADA import/export will
  then carry this information for you, so there is no need to change the
  exporter source code to carry your application/game-specific data into
  the COLLADA format.


This means that sketchup's implementation of it has flaws of implementation for it's a relatively simple to use format, and it just records data and passes it on. So the data recorded might be written improperly by the software.

Blender currently uses the opencollada library to provide support for collada import and export. And as it's open, it's more mature than the rest of the libraries used by other tools that the power of being open.

I believe but there are repos like https://github.com/godotengine/collada-exporter. 
That improve the implementation for game engine Godot.

That's probably all there is to the implementation.